CHICAGO — Masahiro Tanaka will take the mound coming off a regular-season loss Sunday against the White Sox at U.S. Cellular Field for the first time since the end of August 2012 in Japan. Tanaka, 25, went unbeaten over his previous 42 regular-season starts — 34 with the Rakuten Golden Eagles and eight with the Yankees — until the lowly Cubs marred the mark at Wrigley Field Tuesday.

“That’s crazy,” Girardi said Saturday. “We’ll see how he handles it but I’m sure he’ll handle it well like everything else. Maybe it’ll make him mad and he’ll win 44 this time.”

By conventional measures, Tanaka’s outing Tuesday was quality. He surrendered four runs, three earned, over six innings to keep the Yankees within striking distance. But the Yankees’ sputtering offense could not produce much against Jason Hammel and the Cubs bullpen in a 6-1 defeat.

It was Tanaka’s worst outing in the majors, but he still owns a slim 2.39 earned-run average in 64 innings as he has emerged as the Yankees’ best pitcher through nine starts. Entering play Saturday, his 0.97 WHIP was tops in the American League and he was sixth with 73 strikeouts.

But on Tuesday, Tanaka’s famed splitter was ineffective and he uncharacteristically let pitches up in the zone. He is still adjusting to pitching every five days as opposed to once a week like he did in Japan, but he assured his stamina has not suffered.

“We still pay attention to it and how his stuff is responding every fifth day,” Girardi said. “We definitely pay attention to that.”

Whether he’ll revert to the dominant performer he was for most of his first eight starts will be determined Sunday.